项目中 MyBatis 的使用

1.xml 文件

1-1.xml文件格式

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="admin.adminMapper">
</mapper>

1-2.select 语句

<select id="getStudent" parameterType="pd" resultType="pd">
    SELECT *
    from student
    <where>
        <if test="s_id!=null and s_id!=''">
            stuid=#{s_id}
        </if>
        <if test="s_name!=null and s_name!=''">
            and stuname=#{s_name}
        </if>
    </where>
</select>

1-3.其它语句 （以 delete 为例）

<delete parameterType="pd" id="deleteTeacherById">
    DELETE FROM teacher WHERE
    t_id=#{t_id}
</delete>

1-4.模糊查询

name LIKE "%"#{name}"%"

2.传入参数类型

package com.ssm.sample.util;

import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.function.BiConsumer;

import javax.servlet.http.HttpServletRequest;

@SuppressWarnings("rawtypes")
public class PageData extends HashMap implements Map {

    private static final long serialVersionUID = 1L;

    Map<Object, Object> map = null;
    HttpServletRequest request;
    public static void main(String[] args) {
        PageData pageData = new PageData();
        List<PageData> list = new ArrayList<>();
        PageData a=new PageData();
        a.put("key", "asdas");
        list.add(a);
        pageData.put("list", list);
        pageData.put("222", "23232");
        System.err.println(pageData);
    }
    public PageData(HttpServletRequest request) {
        this.request = request;
        Map properties = request.getParameterMap();
        Map<Object, Object> returnMap = new HashMap<Object, Object>();
        Iterator entries = properties.entrySet().iterator();
        Map.Entry entry;
        String name = "";
        String value = "";
        while (entries.hasNext()) {
            
            entry = (Map.Entry) entries.next();
            name = (String) entry.getKey();
            
            Object valueObj = entry.getValue();
            if (null == valueObj) {
                value = "";
            } else if (valueObj instanceof String[]) {
                value = "";
                String[] values = (String[]) valueObj;
                for (int i = 0; i < values.length; i++) {
                    value += values[i] + ",";
                }
                value = value.substring(0, value.length() - 1);
            } else {
                value = valueObj.toString();
            }
            returnMap.put(name, value);
        }
        map = returnMap;
    }

    public PageData() {
        map = new HashMap<Object, Object>();
    }

    public Object get(Object key) {
        Object obj = null;
        if (map.get(key) instanceof Object[]) {
            Object[] arr = (Object[]) map.get(key);
            obj = request == null ? arr : (request.getParameter((String) key) == null ? arr : arr[0]);
        } else {
            obj = map.get(key);
        }
        return obj;
    }

    /**
     * 以安全转换方式获取键值，如果找不到键则返回的值为空
     * 
     * @param key
     * @return
     */
    public String getString(Object key) {
        Object obj = get(key);
        return obj == null ? "" : obj.toString();
    }
    
    /**
     * 以安全转换方式获取键值，如果找不到键则返回的值为null
     */
    public String getStringNull(Object key) {
        Object obj = get(key);
        return obj == null ? null : obj.toString();
    }

    /**
     * 添加键值对
     */
    public Object put(Object key, Object value) {
        return map.put(key, value);
    }
    
    
    /**
     * 移除键
     */
    public Object remove(Object key) {
        return map.remove(key);
    }
    
    /**
     * 清空
     */
    public void clear() {
        map.clear();
    }

    /**
     * 是否包含键
     */
    public boolean containsKey(Object key) {
        return map.containsKey(key);
    }

    public Map<Object,Object> getMap(){
        return map;
    }

    /**
     * 是否包含值
     */
    public boolean containsValue(Object value) {
        return map.containsValue(value);
    }

    public Set entrySet() {
        return map.entrySet();
    }

    public boolean isEmpty() {
        return map.isEmpty();
    }

    public Set<Object> keySet() {
        return map.keySet();
    }

    @SuppressWarnings("unchecked")
    public void putAll(Map t) {
        map.putAll(t);
    }

    public int size() {
        return map.size();
    }

    public Collection<Object> values() {
        return map.values();
    }

    /**
     * 适用jdk8的方法
     */
    @SuppressWarnings("unchecked")
    @Override
    public void forEach(BiConsumer action) {
        this.map.forEach(action);
    }
}

3.Service层

1.baseService

package com.ssm.sample.service.base;

import java.util.Properties;

import javax.annotation.Resource;

import org.mybatis.spring.SqlSessionTemplate;

import com.ssm.sample.util.Logger;

public class BaseService {
    protected Logger logger = Logger.getLogger(this.getClass());
    
    @Resource(name="sqlSessionTemplate")
    protected SqlSessionTemplate sqlSessionTemplate;
    
    @Resource(name = "globalConf")
    protected Properties globalConf;
}

2.UserService

package com.ssm.sample.service.user;

import java.util.List;

import org.springframework.stereotype.Service;

import com.ssm.sample.service.base.BaseService;
import com.ssm.sample.util.PageData;

@Service("UserService")
public class UserService extends BaseService {

    /*
     * 学生
     */
    public List<PageData> getStudent(PageData pd) {
        return this.sqlSessionTemplate.selectList("user.userMapper.getStudent", pd);
    }
}

4.Facade层

1.baseFacade (空的)

2.UserFacade

package com.ssm.sample.facade.user;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import com.ssm.sample.facade.base.BaseFacade;
import com.ssm.sample.service.user.UserService;
import com.ssm.sample.util.PageData;

@Service("UserFacade")
public class UserFacade extends BaseFacade {

    @Autowired
    private UserService userservice;

    /*
     * 获得学生
     */
    public List<PageData> getStudent(PageData pd) {
        List<PageData> list = this.userservice.getStudent(pd);
        return list;
    }    
}

5.Controller层

    /*
     * 学生登录
     */
    @ResponseBody
    @RequestMapping({ "/s_login" })
    public Object s_Login() {
        PageData pd = this.getPageData();

        List<PageData> student = new ArrayList<>();

        Map<String, String> map = new HashMap<String, String>();
        try {
            student = this.userFacade.getStudent(pd);

            if (student.size() != 0) {
                map.put("check", "true");               
            } else {
                map.put("check", "false");
            }

        } catch (Exception e) {
            e.printStackTrace();
        }
        return map;
    }